<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

<form action="" method="post">
    {% csrf_token %}
    <input type="text" name="i1" value="{{ i1 }}">+
    <input type="text" name="i2" value="{{ i2 }}">=
    <input type="text" name="i3" value="{{ i3 }}">
    <button>计算</button>
</form>

</body>
</html>